Article
Geochemistry & Geophysics
Qi Shen, Zhifang Zhou, Meng Chen, Zhe Wang, Yabing Li
Summary: This study focused on the non-Darcian flow characteristics of the interlayer shear weakness zone (ISWZ) and its impact on the stability of hydropower station projects. Two analytical methods for studying non-Darcian flow permeability parameters were proposed and validated through in situ tests. The results showed significant differences in equivalent permeability coefficients before and after destruction, suggesting the importance of considering non-Darcian flow when evaluating ISWZ characteristics for engineering stability.
Article
Engineering, Civil
Wenjun Hua, Yuanjie Xiao, Qunding Yu, Meng Wang, Wenqi Li, Erol Tutumluer, Yuliang Chen, Zhiyong Li
Summary: This paper reveals the meso-scale mechanisms of macroscopic vibratory compaction behavior of unbound aggregate materials (UAMs) and proposes two novel compaction quality indicators based on particle movement characteristics.
TRANSPORTATION GEOTECHNICS
(2023)
Article
Engineering, Civil
Changqing Deng, Yingjun Jiang, Yu Zhang, Yong Yi, Tian Tian, Kejia Yuan, Jiangtao Fan
Summary: This study investigates the mechanical properties of Unbound Graded Aggregate Materials (UGAM) fabricated by vertical-vibration compaction method (VVCM) and establishes a prediction model for dynamic resilient modulus. UGAM fabricated by VVCM exhibits higher California bearing ratio (CBR) and lower aggregate crushing rate compared to samples produced by other compaction methods. The mechanical properties of UGAM increase linearly or nonlinearly with compaction degree, while reducing moisture content enhances the mechanical performance.
TRANSPORTATION GEOTECHNICS
(2021)
Article
Green & Sustainable Science & Technology
Trong Lam Nguyen, Van Tuan Nguyen, Hoang Giang Nguyen, Akihiro Matsuno, Hirofumi Sakanakura, Ken Kawamoto
Summary: The construction industry has high potential for the circular economy and the reuse and recycling of construction and demolition waste (CDW) is crucial for sustainable urban development. This study investigates the practical application of recycled clay brick aggregates (RCBs) and recycled concrete aggregates (RCAs) in unbound roadbed materials in Vietnam through various tests. The results indicate that the maximum amount of RCBs added to RCAs in unbound roadbed materials should be less than 30%. Additionally, the mixing proportions of RCBs and RCAs, maximum aggregate diameter, gradation of aggregates, and initial moisture condition are found to control the saturated hydraulic conductivity. The study also examines the particle breakage characteristics under compaction and proposes an effective method for estimating the mixing proportions of RCAs and RCBs in the fine fraction to understand the particle breakage mechanism.
Article
Engineering, Civil
Yiming Li, Adrian D. Werner, Zhang Wen, Qi Zhu
Summary: This study investigates the impact of non-Darcian flow on solute plume distributions within fractures and faults. It reveals that non-Darcian models result in smaller flow line refraction and specific discharge in preferential flow features, leading to larger peak solute concentrations and narrower plumes compared to Darcian models. The study also shows that non-Darcian flow effects are more pronounced with smaller matrix hydraulic conductivity, larger PFF aperture, and larger incidence angle at the matrix-PFF interface.
JOURNAL OF HYDROLOGY
(2022)
Article
Chemistry, Physical
D. A. Dixon, J. Stone, K. Birch, C. S. Kim
Summary: The NWMO is evaluating Sedimentary and Crystalline geosphere media for a potential Deep Geological Repository (DGR) for nuclear waste. They tested bentonite-aggregate mixtures with different compositions and observed the effect of compaction efforts on densification. The results showed that the materials met the required performance goals for swelling pressure and hydraulic conductivity.
APPLIED CLAY SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Yuhao Wan, Xiaoyan Zhao, Guangze Zhang, Bernd Wuennemann, Sixiang Ling, Caiyun Zeng
Summary: This study investigates the flow behavior of phyllite bimrocks, specifically the impact of block orientation. Permeability experiments were conducted on phyllite bimrocks with different block percentages and sizes. The results show that the flow in phyllite bimrocks transitions from laminar to turbulent under lower hydraulic gradient and does not follow Darcy's law. The Forchheimer equation is found to be more suitable for analyzing the flow behavior compared to the Izbash equation. Furthermore, the hydraulic conductivity of phyllite bimrocks can be calculated based on the coefficients in the Forchheimer equation. The study provides valuable insights for risk assessment and prevention of phyllite bimrock slopes.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Chemistry, Physical
Yuliang Chen, Qunding Yu, Wenqi Li, Yuanjie Xiao, Tao Yang, Zhiyong Li, Xiao Zhi, Pin Deng
Summary: This study analyzed the compaction characteristics of tunneling rock waste (TRW) materials and investigated the effects of gradation and compaction methods on these characteristics. The findings showed that the gravel-to-sand ratio (G/S) based gradation design method effectively differentiated particle packing structures and identified optimal excitation frequency range and vibratory parameter combination.
Article
Environmental Sciences
Yuan Xia, Yong Zhang, Christopher T. Green, Graham E. Fogg
Summary: Upscaling groundwater flow using time-fractional flow equations (t-FFEs) in heterogeneous media reveals different stages of flow dynamics due to varying variance and correlation of hydraulic conductivity (K). The study highlights the importance of considering the time-dependent evolution of flow dynamics in understanding transient groundwater flow.
WATER RESOURCES RESEARCH
(2021)
Article
Geosciences, Multidisciplinary
Anis Younes, Hussein Hoteit, Rainer Helmig, Marwan Fahs
Summary: The mixed finite element method is suitable for simulating fluid flow in heterogeneous porous media, but it can generate unphysical oscillations when used for the transport equation. This work proposes a robust upwind MFE scheme that combines the upwind finite volume method with the hybrid formulation of the MFE method. Numerical simulations show that the new scheme generates stable solutions without oscillations and is robust for solving nonlinear problems.
HYDROLOGY AND EARTH SYSTEM SCIENCES
(2022)
Article
Engineering, Geological
Yong-Min Kim, Tae-Hyuk Kwon
Summary: The use of bacterial biofilms and EPS for engineered bioclogging in geotechnical practices has gained attention, with the addition of fine clay particles enhancing the durability of biofilm-induced bioclogging. Experiments showed that biofilm associated with bentonite particles demonstrated improved resistance against fluid flows compared to biofilms alone, suggesting the potential of bentonite-biofilm aggregations in enhancing bioclogging durability in nutrient-poor conditions.
Article
Soil Science
Smadar Tanner, Itzhak Katra, Eli Argaman, Meni Ben-Hur
Summary: The structure stability and hydraulic conductivity of soils are influenced by various factors such as slaking, swelling, and dispersion. During wetting and leaching processes, sublayer soils have higher structural strength and less breakdown compared to top soils, leading to a lower hydraulic conductivity.
Article
Construction & Building Technology
David Hernando, Richard Smith, Greg Sholar, Bouzid Choubane
Summary: The study aims to investigate the field permeability of thin OGFC layers using an approximate analytical solution based on 2D flow proposed by researchers at UT-Austin. It was found that using vacuum grease hindered permeability, but using closed-cell high-density foam pads as a sealant method can overcome this issue. Additionally, the study emphasizes the importance of ensuring an adequate volume of water during testing to provide accurate measurement results.
CONSTRUCTION AND BUILDING MATERIALS
(2021)
Article
Chemistry, Physical
Yuanjie Xiao, Meng Wang, Xiaoming Wang, Juanjuan Ren, Weidong Wang, Xiaobin Chen
Summary: This study investigated the compaction quality and mechanism of unbound aggregate materials with permeable gradation using laboratory gyratory compaction testing and orthogonal array theory. Real-time particle motion sensors were utilized to provide meso-scale explanations, revealing a significant bilinear relationship between compaction quality and particulate breakage.
Article
Construction & Building Technology
Chonghui Wang, Xiaodong Zhou, Pengfei Liu, Guoyang Lu, Hainian Wang, Markus Oeser
Summary: This paper introduces an integral system to study and simulate the paving compaction of asphalt motorways, using Discrete Element Model and artificial intelligence technology to control and simulate the pavement compaction process.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Engineering, Mechanical
Xiang Liu, Chengli Sun, J. Ranjan Banerjee, Han-Cheng Dan, Le Chang
Summary: An exact dynamic stiffness method is proposed for the free vibration analysis of multi-body systems, allowing connections between rigid bodies and beams of any shape or size. The research examines the role of different beam theories in the dynamic behavior of multi-body systems, providing exact benchmark results compared with finite element solutions. This study offers an efficient analysis tool for multi-body system dynamics, suitable for optimization and modal parameter identification.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Environmental Sciences
Bo Xu, Yaolin Yi
Summary: LFS, a by-product of the steel industry, is difficult to reuse due to its weak cementitious property and potential leaching of heavy metals. This study aimed to use CO2 to immobilize heavy metals in LFS and enhance its strength. Results showed that LFS had carbonation reactivity and could sequester CO2 up to 9.6% of its own mass, effectively reducing leaching of heavy metals and increasing strength.
Article
Engineering, Mechanical
Xiang Liu, Le Chang, J. Ranjan Banerjee, Han-Cheng Dan
Summary: This paper introduces a closed-form dynamic stiffness formulation for non-uniform beams, as well as improvements in solution techniques. The results demonstrate that the method can accurately and efficiently conduct modal analysis, without the need for series solutions, numerical integrations, or refined mesh discretization.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Green & Sustainable Science & Technology
Han-Cheng Dan, Hao-Fan Zeng, Zhi-Heng Zhu, Ge-Wen Bai, Wei Cao
Summary: In this study, an interactive labeling method based on the U-Net convolutional neural network is proposed for accurate and efficient recognition of pavement patching images. The results show that this method achieves higher accuracy and reduces noise compared to traditional methods.
Article
Chemistry, Multidisciplinary
Jiaqi Chen, Xingzao Chen, Hancheng Dan, Lanchun Zhang
Summary: This paper developed a combined prediction method for the thermal conductivity of asphalt concrete and verified its accuracy through laboratory experiments. The study found that the orientation angle and aspect ratio of aggregate have a combined effect on thermal conductivity, with asphalt concrete showing greater thermal conductivity in the direction parallel to aggregate orientation.
APPLIED SCIENCES-BASEL
(2022)
Article
Construction & Building Technology
Hancheng Dan, Liansheng Gao, Hao Wang, Jin Tang
Summary: This study analyzes the wearing behavior of asphalt mixtures under repetitive tire loads using discrete element modeling and develops a conversion method to predict the long-term value of mean texture depth (MTD).
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
(2022)
Article
Construction & Building Technology
Han-Cheng Dan, Zhi Zhang, Jiaqi Chen, Wei Cao
Summary: This study used the three-dimensional discrete element method (DEM) to evaluate 16 different configurations of the single-edge notched bend (SENB) test with different notch offset levels. The simulation results were analyzed from macroscopic and mesoscopic perspectives. The macroscopic analysis revealed three types of crack morphology and explained the factors affecting the main crack deflection angle. The study also found that low-temperature crack resistance is influenced by beam bending deformation and microcrack damage evolution. At the meso-level, the DEM model provided a realistic visualization of the crack propagation process and accurately captured the mesoscopic contact failure mechanism.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Engineering, Environmental
Jiawei Tan, Ozlem Cizer, Jentel De Vlieger, Hancheng Dan, Jiabin Li
Summary: This study investigates the effects of milling duration on CDW-based precursors and resulting geopolymer paste and finds that longer milling enhances reactivity and leads to higher strength and lower CO2 emissions in geopolymer derived from CDW.
RESOURCES CONSERVATION AND RECYCLING
(2022)
Article
Materials Science, Multidisciplinary
Han-Cheng Dan, Chongyu Ling, Zhiheng Zhu, Liansheng Gao, Xiaojun Zeng
Summary: This study focuses on the rationality of traffic data analysis and the scientificity of maintenance decision-making in road maintenance. By using a fusion of multiple traffic data sources, the study investigates the recovery of vehicle type and axle load information, distribution probabilities of traffic volume, estimation of equivalent standard axle load, and analysis of axle load spectrum and distribution characteristics. The results show significant differences when considering rutting depth, which may greatly affect the accurate determination of preventive maintenance timing.
FRONTIERS IN MATERIALS
(2022)
Article
Environmental Sciences
Bo Xu, Yaolin Yi
Summary: This study introduces a sustainable method for immobilization of lead using industrial solid waste and greenhouse gas. Carbonation curing of ladle furnace slag effectively immobilizes lead and reduces leaching concentrations. This method also sequesters carbon dioxide, reduces costs, resource and energy consumption, and landfilling of waste materials.
Article
Chemistry, Physical
Hancheng Dan, Penghao Yang, Wei Cao, Hongyu Shan, Zhi Zhang
Summary: In this study, a convenient experimental setup was developed to simulate in situ stress conditions in the laboratory. The results showed a significant dependence of the confined modulus on temperature, frequency, and compactness, with coarser gradation mixtures demonstrating less sensitivity to these parameters. A mathematical model was developed to unify these factors using the time-temperature superposition principle and shift factors for confinement and compactness.
Article
Chemistry, Physical
Zhiming Ma, Hancheng Dan, Jiawei Tan, Mengjin Li, Songlin Li
Summary: There are several influencing factors in the preparation of MK-GGBS-based geopolymer repair mortars, and the interactions between these factors are not fully understood. Therefore, response surface methodology was used to optimize the preparation of the repair mortar, and the optimized mortar meets the standard's requirements for various properties. The back-scattered electron images and energy dispersive spectroscopy analysis show good interfacial adhesion and a denser interfacial transition zone in the optimized proportion.
Article
Construction & Building Technology
Hancheng Dan, Zhiming Ma, Mengjin Li, Shenglong Ma, Jiawei Tan
Summary: Metakaolin (MK) and ground granulated blast furnace slag (GGBS) based geopolymers have been studied for their use in concrete road repair. This research investigated the workability, early strength development, and bonding mechanism of these geopolymer repair mortars with varying GGBS contents. The study revealed that higher GGBS content in geopolymer repair mortars resulted in shorter setting times, higher flowability, and higher compressive strength. Geopolymers showed a rod-shaped nucleation pattern during hardening, with the crystallization rate decreasing as GGBS was added. The addition of GGBS increased the formation of C-A-S-H gels and accelerated the geopolymerization process. However, excessive GGBS reduced bond strength due to the introduction of microcracks. The recommended GGBS content was found to be 60 wt.%. The study also found that the cement substrate could absorb alkali activator, leading to the formation of high-Ca gels and strengthening the interface.
INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING
(2023)
Article
Chemistry, Physical
Zhi Zhang, Hancheng Dan, Songlin Li, Wenfeng Li
Summary: This study uses SmartRock sensor technology to investigate the dynamic response and compaction degree variations of different asphalt surface courses during vibrational compaction. It establishes a correlation between triaxial aggregate acceleration and compaction degree, providing a basis for predicting asphalt surface course density.
Article
Engineering, Environmental
Bo Xu, Junde Qin, Yaolin Yi
Summary: This study introduces an innovative approach by reusing industrial waste and greenhouse gas for fast immobilization of zinc, providing triple benefits of immobilizing zinc, mitigating waste landfilling, and capturing CO2.
RESOURCES CONSERVATION AND RECYCLING
(2023)
